Something has happened to the Iowa football team on its way to becoming a dominant force on the ground this season.

Senior right tackle Brett Van Sloten believes he has the answer.

“That starts up front with us five guys on the offensive line,” Van Sloten said. “We’re not doing our job to give the running backs and opportunity to do what they do best.

“The coaches can tell us who to block on each play, but it comes down to us executing.”

Van Sloten is partly correct in saying that the offensive line has to execute better, as junior running back Mark Weisman is correct in saying the same thing about the players at his position.

There is more to it than that, though.

The schedule also has kept Iowa from becoming a dominant rushing team this season, perhaps more than anything else.

It took nearly half of the season for it to happen, but the 2013 schedule has exposed the Iowa running game for being average to below average against quality defenses.

It probably won’t matter when Iowa (5-4) plays at lowly Purdue (1-7) on Saturday because to say that Purdue struggles on defense is like saying Miami Dolphins suspended offensive lineman Richie Incognito struggles with player relations. The Boilermakers are ranked last in the Big Ten in rushing defense, 11th in scoring defense and 10th in total defense.

Purdue is similar on defense to Missouri State, Iowa State and Western Michigan and you saw what Iowa did in those three non-conference victories, rushing for more than 200 yards in each game, including a season-high 296 yards against FCS member Missouri State.

Iowa kept its foot on the gas against Minnesota in the Big Ten opener, shredding the Gophers for 246 rushing yards during a 23-7 victory on Sept. 28 in Minneapolis. That stands as Iowa’s most impressive victory this season, with the Gophers now a surprising 7-2 overall.

Iowa averaged a whopping average of 244.0 rushing yards through the first five games. But in the last four games that average has dropped to just 101.0 rushing yards per contest and Iowa has averaged fewer than 4 yards per carry. The low point was the 26-14 loss to Michigan State on Oct. 5, when Iowa was held to 23 yards on 16 carries.

Wisconsin held the Hawkeyes to 115 rushing yards on 32 carries during Saturday’s 28-9 victory at Kinnick Stadium.

“We’ve gone up against some good defenses, but most of it falls on us as an offensive line to get it going and open up the running lanes that need to be there for them,” said Iowa sophomore center Austin Blythe.

There is no finger pointing on this Iowa team, only mirrors. That’s cause for the hope.

The remaining schedule which, in addition to Purdue, has games against Michigan and Nebraska, also might be cause for hope because neither the Wolverines nor the Cornhuskers are considered elite on defense. Michigan has performed better against the run this season, although Michigan State running back Jeremy Langford rushed for 120 yards in last Saturday’s 29-6 victory over the Wolverines.

Nebraska continues to be a sieve on defense and is currently ranked ninth in the conference in rushing defense, allowing 182.6 yards per game.

Iowa should have enough weapons in its running game to climb out of its funk. But you’re still left wondering when the Hawkeyes will deserve the title of Big Ten Bullies again.

To earn that distinction, it shouldn’t matter who Iowa faces on defense.

Wisconsin deserves the title of Big Ten Bullies more than any team at this stage and it’s been that way for quite a while now.

Iowa has produced its share of NFL offensive linemen during Kirk Ferentz’s coaching reign, which dates back to 1999. But it’s been a while since the Hawkeyes have had a truly dominant offensive line, perhaps as far back as 2002.

Ferentz climbed up the coaching ladder as an offensive line coach, so to struggle in that area strikes at the very core of Iowa football under his watch. His oldest son, Brian Ferentz, now coaches the Iowa offensive line, but his father is never far away.

Perhaps that’s why Kirk Ferentz seemed a little defensive Tuesday when asked about his team’s recent rushing woes. He brought up the Ohio State game in which Iowa rushed for 130 yards on 27 carries, saying he felt the rushing attack did fairly well.

But he conceded that the running game leaves something to be desired.

“I’m not overly thrilled with what we’re doing right now,” Kirk Ferentz said. “We need to amp that up a little bit.”

Weisman has been similar to his offensive line in how he has dominated lesser opponents and struggled against elite defenses. He rushed for more than 100 yards in four of the first five games, but has failed to reach 60 yards in each of the last four games.

The stretch play that has made Weisman so effective against the lesser defenses hasn’t worked in the last four games. It takes too long for the play to develop against defenses that pursue well laterally, especially with Weisman dealing with the aches and pains that are common in November.

Purdue doesn’t fall into that category, though, so don’t be surprised if Weisman breaks loose again Saturday.

About Pat Harty: Columnist Pat Harty has been covering the Iowa Hawkeyes for the Press-Citizen since 1991. Originally from Des Moines, he currently writes columns and covers Hawkeye men's basketball for Hawk Central. View author profile.